There are two ways that you can remove your transmission (also known as the gearbox) from the motorcycle.  The engine and transmission can be removed as a single unit, or you may also remove the transmission only, leaving the engine in place.

In order to remove the motor and transmission from the motorcycle in a single unit, you must begin with the basics.  First you should place the motorcycle on the center stand if it is a solo model, however sidecar equipped models do not necessitate using the center stand. 

   Drain the fuel from the fuel tank.  You might wish to take this opportunity to check your fuel filters for any debris which may hinder fuel flow.  You might also choose to remove the fuel petcock and inspect it for debris gathered inside the fuel tank.  Once the tank is drained you will need to remove it.  There are two bolts at the front of the fuel tank attaching it to the frame just behind the front fork in the neck area.  There are two more fasteners at the rear of the tank, underneath the frame tank support.  These are a nut and bolt combination with a rubber grommet to absorb vibration.  There is also a fuel tank equalization hose located under the fuel tank, and you will need to remove at least one side of this hose.  This hose is the same diameter as your fuel line, and is an often neglected  and becomes dry rotted and cracked which will eventually lead to fuel leakage.  You don’t want that to happen as the fuel will leak onto your hot motor and possibly catch on fire, so you should inspect this line as often as you inspect your fuel lines.

   Remove the nuts which are located on the motor mount studs that run through the lower frame rails and the engine.  There are four of them, two on each side.  The two on the front stud also double as exhaust pipe bracket clamp fasteners and they must be removed to allow the exhaust pipes to be removed.  Now you are ready to remove the exhaust system.  First you should remove the special nuts which hold the header pipes securely fastened to the cylinder heads.  There may also be a second set of special nuts which seal the header pipes with the mufflers.  Not all models use this type of fasteners especially if you have had aftermarket mufflers installed for better breathing and sound.  Remove the mufflers from the header pipes, and the header pipes from the cylinder heads.  If your exhaust has a receiver you will need to remove the special nut attaching the receiver to the L.H. muffler.  Next you need to remove the receiver from the rear motor mount stud. 

   Next you should remove the footrests which are also bolted onto the motor mount studs.

   Now you need to remove the air filter box from the carburetors and from the rear of the engine.  If you have inertia-oil type air filter, first disconnect the rubber hose that connects your crankcase breather (located at the rear of the front left engine case) to the air filter.  There are two screws which are located in the gearbox neck that hold the air filter in place. These need to be loosened in order to remove the air filter.  Pull the filter upwards and to the rear of the compartment to loosen the air box, then while depressing the kicker lever remove to the L.H. side.  If your air filter is the paper element type, you must firs disconnect the rubber air pipes, the air pipe and the breather pipe.  Remove the clutch cable envelope fastening screw, undo the two nuts locking the filter bracket onto the transmission and remove the filter. 

   To remove the R.H. & L.H. cylinder steel air pipes first release the clips, detach the air pipes from the carburetors and remove them from the gearbox neck.  To remove the rubber air pipes, turn them clockwise and counter clockwise and pull them gently.

   Disconnect and remove the battery being sure that you do not short circuit the wiring.  Some models are equipped with an interrupt switch under the seat on the frame.  Remove the nut that secures the battery retainer clip, and remove the battery.  Do not place the battery on a concrete surface.  Place the battery on a piece of wood or the work bench to prevent drainage and damage.

   Disconnect the wires from the generator terminals, marking them with a bit of masking tape.  I take a yellow marker and designate the terminals 1,2&3 directly on the generator, and mark the corresponding wires in the same manner on the tape.  This will help to prevent hooking the wires up to the wrong terminals when you re install the engine.  There is also a low voltage indicator terminal and a conductor to the oil pressure sending unit which will need to be disconnected, along with the conductor for the transmission neutral sender.

   Remove the Carburetor covers and withdraw the carburetor slides from the carburetor bodies.  You can either disconnect the throttle control handle cables from the throttle bodies, fitting the carburetor slides and covers back in their places, or you can simply hand the slide assemblies still attached to the throttle cables around your handlebars and cover the carburetor bodies with a clear or foil wrap.

   Disconnect the clutch cable from the clutch throw out lever, and remove the clutch cable from the cable envelope clamp.

CABLE ENVELOPE CLAMP

   On the transmission, where the speedometer cable goes into the gearbox, there is a bolt which holds the drive bush in place.  Loosen this bolt and lift he speedometer cable from the housing and put it somewhere out of the way.  (I use a wire tie to hold the cable to the frame backbone.)

   Remove the nuts from the top motor mount and disconnect the frame conductor being sure to mark it using masking tape.  If you have a sidecar you will need to back off the sidecar link bracket several turns to ease it off so you can lift off the upper motor mount.

   Put the bike into first gear, and using the starter crank, turn the bike over so that the two pins that go into the rubber coupling disk are arranged vertically (up and down).  If you have not lifted the bike onto the center stand, you should lift the rear wheel off of the ground to accomplish this without the bike moving foreword. 

   You may now remove the motor mount studs, beginning with the rear stud.  This can be driven out using a long punch, being sure not to damage the motor mount stud threads.  I have found that a scissor-jack or a hydraulic jack is very helpful for relieving binding stress and allowing the studs to be removed more easily. Now you can remove the front motor mount stud, tilting the engine slightly to the R.H. side to keep the generator on the frame right.  Lift up the generator and remove it to the left.

   It is best to have someone else available to help lift the motor and transmission assembly out of the frame cradle, as the unit is quite heavy and more than a bit awkward.  I have found that a simple box made from 4 2x4”s makes an excellent engine cradle and helps to prevent the assembly from rolling around. 

   I also have found that a deep sump oil pan makes it very difficult to remove the engine, and so I drain the oil, and remove the pan before removing the engine and transmission assembly.  If you do this be sure to remove the oil level indicator (dipstick) before you put the engine down on the ground or bench or it may become damaged.

   It is also possible to remove the transmission from the motorcycle without removing the engine as well; however I personally find this method to be a little more difficult.

   For this method you must place the motorcycle on the center stand.   You need to do this so that you can remove the rear wheel.

   Once the motorcycle is up on the center stand you remove the rear wheel by first loosening the pinch bolt on the L.H. side of the swing arm where the axle goes through.  On the R.H. side of the axle is a cotter pin that needs to be removed so that the castle nut holding the axle into place can be taken off.  Pull the axle out to the L.H. side being careful not to drop the hub deflector.  If you have difficulty removing the axle you can put a drift pin or heavy screwdriver through the hole in the axle and use it to make a gripping handle to pull on.  Pull the wheel t

o the left and remove it from the frame.  You may need to loosen the mud guard to get the wheel free from the frame and fender.

   Remove the four rear drive case nuts that attach the differential to the swing arm.  (Leading fork tenon)  Remove the final drive from the swingarm.  Remove the rubber disk assembly with the rubber bush from the transmission coupling disk pins.

   You will also need to disconnect your brake accentuating rod.  I choose to disconnect the brake rod at the pivot lever as the brakes will generally need to be readjusted after being re assembled.

   Remove the carburetor intake pipes. 

   Now you need to remove the air filter box from the carburetors and from the rear of the engine.  If you have inertia-oil type air filter, first disconnect the rubber hose that connects your crankcase breather (located at the rear of the front left engine case) to the air filter.  There are two screws which are located in the gearbox neck that hold the air filter in place. These need to be loosened in order to remove the air filter.  Pull the filter upwards and to the rear of the compartment to loosen the air box, then while depressing the kicker lever remove to the L.H. side.  If your air filter is the paper element type, you must firs disconnect the rubber air pipes, the air pipe and the breather pipe.  Remove the clutch cable envelope fastening screw, undo the two nuts locking the filter bracket onto the transmission and remove the filter.

    Disconnect and remove the battery being sure that you do not short circuit the wiring.  Some models are equipped with an interrupt switch under the seat on the frame.  Remove the nut that secures the battery retainer clip, and remove the battery.  Do not place the battery on a concrete surface.  Place the battery on a piece of wood or the work bench to prevent drainage and damage.

    Disconnect the clutch cable from the clutch throw out lever, and remove the clutch cable from the cable envelope clamp.

   On the transmission, where the speedometer cable goes into the gearbox, there is a bolt which holds the drive bush in place.  Loosen this bolt and lift he speedometer cable from the housing and put it somewhere out of the way.  (I use a wire tie to hold the cable to the frame backbone.)

   Remove the three nuts that lock the studs that attach the transmission to the engine and the bolt which is located on the front of the lower R.H. side of the engine crankcase.  Pull the transmission rearward and remove to the L.H. side.